1. Field of the Invention
The invention generally related to a semiconductor structure and a method of making the same. More particularly, the invention related to a method of fabricating a high-k metal gate semiconductor device.
2. Description of the Prior Art
As the size of the integrated circuit devices continues to scale down, the polysilicon gate and the silicon dioxide insulating layer of a metal-oxide-semiconductor field effect transistor (MOSFET) structure have been confronted with the physical limits of the material itself. To meet the demands of scalability, it is necessary to incorporate high-k metal gate (HK/MG) process.
Today, two main integration options remain: gate-first (often referred to as MIPS, metal inserted poly-silicon) and gate-last (also called RMG, replacement metal gate). The terminology “first” and “last” refers to whether the metal electrode is deposited before or after the high temperature activation anneal of the flow. The replacement metal gate (RMG) process flow allows the use of aluminum as a conductor material.
In conventional HK/MG process, the dummy poly silicon gate line is segmented (also called poly cut) before the source/drain epitaxial growth process. As a result, the epitaxial extrusion defect is very possible to occur at the distal ends of the dummy poly silicon gate segments, which impacts the process yield. Therefore, there is a need in this technical field to provide an improved semiconductor structure and manufacturing process to overcome the deficiencies described hereinabove.